The spacecraft was part of the Vostok programme in which six manned spaceflights were made from 1961 to 1963. Two further manned space flights were made in 1964 and 1965 by Voskhod spacecraft, which were modified Vostok spacecraft. By the late 1960s both were superseded by the Soyuz spacecraft, which are still used as of 2014[update].

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The Vostok spacecraft was originally designed for use both as a camera platform (for the Soviet Union's first spy satellite program, Zenit) and as a manned spacecraft. This dual-use design was crucial in gaining Communist Party support for the program. The basic Vostok design has remained in use for some forty years, gradually adapted for a range of other unmanned satellites. The descent module design was reused, in heavily modified form, by the Voskhod program.

The craft consisted of a spherical descent module (mass 2.46 tonnes, diameter 2.3 meters), which housed the cosmonaut, instruments and escape system, and a conical instrument module (mass 2.27 tonnes, 2.25 m long, 2.43 m wide), which contained propellant and the engine system. On reentry, the cosmonaut would eject from the craft at about 7,000 m (23,000 ft) and descend via parachute, while the capsule would land separately.

There were several models of the Vostok leading up to the manned version:

The Vostok capsule had limited thruster capability. As such, the reentry path and orientation could not be controlled after the capsule had separated from the engine system. This meant that the capsule had to be protected from reentry heat on all sides, thus explaining the spherical design (as opposed to Project Mercury's conical design), which allowed for maximum volume while minimizing the external surface. Some control of the capsule reentry orientation was possible by way of positioning of the heavy equipment to offset the vehicle center of gravity, which also maximized the chance of the cosmonaut surviving g-forces while in a horizontal position. Even then, the cosmonaut experienced 8 to 9g.